In Short-Lived Fish, Secrets to Aging

Posted on February 27, 2015May 24, 2020 by admin

The New York Times, February 27, 2015

The turquoise killifish lives in a fleeting world: the ponds that appear only during the rainy season in East Africa.

As a new pond forms, turquoise killifish eggs buried in the mud spring from suspended animation. The eggs hatch, and in just 40 days the fish grow to full size, about 2.5 inches. They feed, mate and lay eggs. By the time the ponds dry up, the fish are all dead.

Even when hobbyists pamper them in aquariums, turquoise killifish survive only a few months, making them among the shortest-lived vertebrates on Earth. So the turquoise killifish may not seem the best animal to study to discover the secrets of a long life.

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Is It Worth Imagining Airborne Ebola?

Posted on February 22, 2015September 24, 2018 by admin

EBOLA VIRUS. MICROGRAPH FROM CDC/CYNTHIA GOLDSMITH

Back in September, when the West African Ebola outbreak was getting worse with every passing week, a lot of people began to worry that the virus could spread by air. And even if it couldn’t spread by air yet, they worried that it might be on the verge of mutating into an airborne form.

When I talked to virus experts, they saw little ground for either concern. The epidemiology of the outbreak, like previous ones, had the sort of pattern you’d expect from a virus that spreads mainly through contact with body fluids. A look at the evolutionary history of viruses indicates that a fluid-adapted virus would be unlikely to switch to going airborne with just a couple mutations. (I wrote in the New York Times about these conversations here and here.)

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A New Theory on How Neanderthal DNA Spread in Asia

Posted on February 19, 2015May 24, 2020 by admin

The New York Times, February 19, 2015

Link

In 2010, scientists made a startling discovery about our past: About 50,000 years ago, Neanderthals interbred with the ancestors of living Europeans and Asians.

Now two teams of researchers have come to another intriguing conclusion: Neanderthals interbred with the ancestors of Asians at a second point in history, giving them an extra infusion of Neanderthal DNA.

The findings are further evidence that our genomes contain secrets about our evolution that we might have missed by looking at fossils alone. “We’re learning new, big-picture things from the genetic data, rather than just filling in details,” said Kirk E. Lohmueller, a geneticist at the University of California, Los Angeles, and co-author of one of the new studies.

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Studying Oversize Brain Cells for Links to Exceptional Memory

Posted on February 12, 2015May 24, 2020 by admin

The New York Times, February 12, 2015

Link

In 2010, a graduate student named Tamar Gefen got to know a remarkable group of older people.

They had volunteered for a study of memory at the Feinberg School of Medicine at Northwestern University. Although they were all over age 80, Ms. Gefen and her colleagues found that they scored as well on memory tests as people in their 50s. Some complained that they remembered too much.

She and her colleagues referred to them as SuperAgers. Many were also friends. “A couple tried to set me up with their grandsons,” Ms. Gefen said.

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Parasitic Wasps Infected with Mind-Controlling Viruses

Posted on February 10, 2015September 24, 2018 by admin

In November, National Geographic put a ladybug and a wasp on its cover. They made for a sinister pair. The wasp, a species called Dinocampus coccinellae, lays an egg inside the ladybug Coleomegilla maculata. After the egg hatches, the wasp larva develops inside the ladybug, feeding on its internal juices. When the wasp ready to develop into an adult, it crawls out of its still-living host and weaves a cocoon around itself.

As I wrote in the article that accompanied that photograph, the ladybug then does something remarkable: it becomes a bodyguard. It hunches over the wasp and defends it against predators and other species of parasitic wasps that would try to lay their eggs inside the cocoon. Only after the adult wasp emerges from its cocoon does the bodyguard ladybug move again. It either recovers, or dies from the damage of growing another creature inside of it.

How parasites turn their hosts into zombie slaves is a tough question for scientists to answer. In some cases, researchers have found evidence suggesting that the parasites release brain-controlling chemicals. But the wasp uses another strategy: there’s a parasite within this parasite.

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